GB2201053A - Failsafe headlamp control apparatus for a vehicle - Google Patents
Failsafe headlamp control apparatus for a vehicle Download PDFInfo
- Publication number
- GB2201053A GB2201053A GB08805046A GB8805046A GB2201053A GB 2201053 A GB2201053 A GB 2201053A GB 08805046 A GB08805046 A GB 08805046A GB 8805046 A GB8805046 A GB 8805046A GB 2201053 A GB2201053 A GB 2201053A
- Authority
- GB
- United Kingdom
- Prior art keywords
- headlamps
- terminal
- capacitor
- microcomputer
- vehicle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
- B60Q11/00—Arrangement of monitoring devices for devices provided for in groups B60Q1/00 - B60Q9/00
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
- B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
- B60Q1/02—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments
- B60Q1/04—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments the devices being headlights
- B60Q1/14—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments the devices being headlights having dimming means
- B60Q1/1415—Dimming circuits
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Lighting Device Outwards From Vehicle And Optical Signal (AREA)
Description
1 1 r.
22010 5"3 Q3757GB/ALM/JACf Description of Invention "Light Control Apparatus. for a Vehicle" THE PRESENT INVENTION relates to light control apparatus for a vehicle which automatically turns a vehicle headlamp on or off.
A known circuit for controlling vehicle lights is shown in Figure 4 of the accompanying drawings. In Figure 4, 1 is a battery, 2 is a main fuse, 3 is an ignition switch, 4 is a control unit, 5 is a light sensor, 6A and 6B are headlamps, 7A and 7B are small lamps, 8 is a headlamp driving relay, 9 is a small lamp driving relay, 10 is a switching unit and 11 to 14 are fuses. The power supply to the unit 4 is from the battery 1 through the ignition switch 3.
In the OFF condition of the switching unit 10, (open circuit conditions of the switches AUTO, SMALL and HEAD) the terminals AUTO, SMALL and HEAD of the control unit 4 are all on open circuit. Upon selection of the switch (mode) SMALLi the terminal SMALL only of the unit 4 is closed and the other terminals remain open. Upon selection of the switch HEAD, the terminals SMALL and HEAD of the unit 4 are closed and terminal AUTO remains open. Upon selection of the' switch AUTO, only the terminal AUTO of the unit 4 is closed and the other terminals remain open, and the headlamps 6A, 6B and the small lamp 7A, 7B are driven through the respective relays. The light sensor 5 is connected to the unit 4 with three lines of a power source line, a sensor output line and a grounding (GND) line.
11, - When the switch HEAD of said lighting switch is selected, the terminals SMALL and HEAD of the unit 4 are closed, and both relays 8 and 9 are energised so that the headlamps 6A, 6B and the small lamps 7A, 7B are turned on. In the case of the switch SMALL being selected, the terminal SMALL of the unit 4 is energized to complete the current path, and the relay 9 is energized to turn on the small lamps 7A and 7B. When the switch AUTO is selected, the terminal AUTO of the unit 4 is closed, and the headlamps 6A and 6B are turned on or off in accordance with the output of the light sensor 5 supplied via the control unit 4.
In this way, by selecting the automatic mode of the switching unit 10, turning on or off of the headlamps is automatically controlled; however, the above configuration has the following disadvantages.
Since the power source supply relies on only one system, if one of the units of the fuse system has problems, even if the main unit has no problems, excessive current is generated, and when the fuse melts all the headlamps are turned off, bringing about very dangerous conditions for night driving.
(2) Since the power source supply relies on only one cable and"further a connector is used in connecting the unit, a loose contact or a break in the cable affects the controlling of the lamp and reduces reliability.
The headlamps are turned on or off by the output of the light sensor 5; however, a connector is used in connecting the sensor 5 to the unit 4 and this causes the problem of reduced contact reliability.
(4) Unless the terminal AUTO is in a completely closed j 1 7_ condition, because of the structure of the switching unit 10 there is a possibility that a manual mode may be generated and the headlamps turned off. Most of the recent switching units are of the types having direct coupling, since each signal is distributed through the connector, if the terminal AUTO relies on only the contact of the connector; the problem of reliability described in item (2) above remains.
(5) Since the headlamps -are driven by only one relay, reliability is restricted to that of one relay.
(6) In the case of microcomputer runaway or failure, there is a possibility that the headlamps may be suddenly turned off, so that safety during driving can not be assured.
An object of the present invention is to provide a highly reliable lighting control apparatus for a vehi cle.
Accordinglyg the invention provides apparatus for enabling the headlamps of a vehicle to be controlled automatically in response to ambient light levels outside the vehicle, in which apparatus control means are provided to control the headlamps of a vehicle in response to ambient light levels and means are provided for maintaining operation of the headlamps should the control means fail, the maintaining means comprising a capacitor connected to receive a pulsed signal from the control means to charg e the capacitor an unstable oscillatory circuit arranged to commence oscillation when the capacitor is charged to a predetermined voltage to apply a reset signal to the control_ means, and a by- pass circuit for supplying signals to maintain th e headlamps in an on condition when the capacitor discharges so that operation of the headlamps is k maintained even if the control means fails.
In order that the invention may be readily understood an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a wiring diagram showing one embodiment of lighting control apparatus for a vehicle in accordance with the present invention; Figure 2 is a circuit diagram of a control unit of the apparatus; Figure 3 is a circuit diagram for a case in which one headlamp-driving relay is used; and Figure 4 is a circuit diagram of a known lighting control apparatus for a vehicle.
- Referring now to the drawings, Figure 1 and Figure 2 show an embodiment of the present invention in which 21 is a battery 22 is a main fuse, 23A and 23B are ignition switches, 24 is a control unit, 25 is a light sensor, 26A and 26B are headlamps, 27A, 27B are small or side lamps, 28A and 2813 are headlamp driving relays, 29 is a small lamp driving relay, 30 is a switching unit, 31 to 36 are fuses and 37 is a warning lamp. The two terminals IGI and IG2 of the control unit 24 are supplied with power through two separate paths via the ignition switches 23A and 23B and two paths to ground are provided via the two terminals GNDI and GND2. Regarding the connections of the light sensor 25 to the unit 24, double grounding lines extend from the sensor 25 to the two grounding terminals SG1 and SG2 of the unit 24. An output signal line of the light sensor 25 is connected to the terminal SO of the control unit and a power supply line is t.' 1 1 connected to power source terminal SP of the control unit.
1 As regards the operation of the switching unit 30, in an OFF condition thereof only the terminal AUTO of the unit 24 is closed and the remaining terminals SMALL, HEAD1 and HEAD2 are open. When the mode switch SMALL is selected, _the terminals AUTO and SMALL of the unit 24 are closed and the remaining terminals HEAD1 and HEAD2 are open. When the mode switch AUTO is selected, the terminals AUTO, SMALL, HEAD1 and HEAD2 of the unit 24 are all open. When the mode switches HEAD1 and HEAD2 are selected, the terminals AUTO, HEAD1 and HEAD2 of the unit 24 are closed and the remaining terminal SMALL is open.
The headlamps 26A and 26B are driven through two respective parallel paths through the two relays 28A and 28B.
A warning lamp 37 indicates whether there is an abnormal condition in the power sources or the headlamp driving relays of the two systems. Even if only one of the systems has a fault, this is indicated by the alarm.
Figure 2 showsthe circuit configuration of the control unit 24, mainly implemented as a microcomputer 240 and other equipment providing a headlamp trouble detection circuit 241, a power source fault detection circuit 242, an output processing circuit 243 for the light sensor 25 (implemented as operational amplifiers IC2-A to IC2-D, resistors R1 to R11, capacitors C4 to C8 etc.), a fail-safe circuit 244 (implemented by capacitors C22 to C24, diodes D9, D10 etc.) which exerts the fail safe function for the microcomputer's runaway, and the circuit to which the microcomputer 240 and the terminals WARN, AUTO, SMALL are connected.
The headlamp fault detection circuit 241_ is for - A detecting faults in the headlamp driving system. The arrangement for the terminal HEAD1 and HEAD2 side is the same for each terminal. Thus, for the terminal HEAD1 a resistor 29, an inverter IC3-Eg resistor R33 and the resistor R62 are connected in series between the terminal Co of the microcomputer and the terminal HEAD1 while a resistor R31 and a capacitor C14 are connected in parallel from a connection between resistors 33 and 62 to ground. Similarlyg the terminal Cl of the microcomputer 240 is connected to the terminal HEAD2 by the series of arrangement of resistor R30, inverter IC3-F and resistors R34 and R53, a connection between the resistors R34 and R63 being connected to earth by resistor R32 in parallel with capacitor C15..
The above described power source abnormal condition detecting circuit 242 is for detecting power source trouble due to fuse me.1ting, loose contact of connector and etc.,' and identical circuits are provided for both of the terminals IGI and IG2. Thus, a series circuit between the terminal IG2 and the terminal C2 of the microcomputer 240 comprises, in order, a diode D12 a resistors 73 and 75, an inverter IC3-A and a resistor 76, a connection between the resistors 73 and 75 being connected to earth via a resistor R74 connected in -parallel with a capacitor C25. Similarly, the terminal IG1 is connected to the terminal C3 of the microcomputer by, in series, a diode D13, resistors 77 and 79, an inverter IC3-B and resistor R80, a connection between resistors 77 and 79 being connected to earth via a resistor R78 connected in parallel to a capacitor C2.
When an abnormal condition is detected by the above detecting circuits 241 and 242, a I'Ll' (low) level signal is provided at port B4 by the microcomputer so that the terminal WARNING becomes I'Ll' level and the warning lamp 37 is turned on to indicate the alarm for abnormal a conditions.
The fail-safe circuit 244, which operates when the microcomputer 240 "crashes" or fails in runaway, is explained next.
IC6-A is a transistor in an open-collector configuration, IC3-D is an inverter, IC4 is a switching regulator and IC5-A to IC5-D are "logic" gates wired to act as inverters. Thus gates IC5-A and IC5-C are NOR gates and gates IC5- B and IC5-D are NAND gates.
The microcomputer 240, when used in the lighting control apparatus for a vehicle, is the main part of the controls unit, and control turning on or off of the headlamps in accordance with the output of the light sensor. The microcomputer has a port BO, a port B5 whi-ch generates pulses with a constant period under the normal operation, a reset terminal RES and a power source terminal Vec etc. D3, D9 and D10 are diodes, R16, R23, R54, R56, R65 to D69, R72 and R84 are resistors, Cl to C3, C9, C20, C22 to C24 and C29 are capacitors, D6 is zener diode and x is a crystal oscillator. The zener diode D6 'is connected between the terminal HEAD1 and ground. The terminal HEAD1 is connected to the output port BO of the microcomputer 240 through the transistor IC6-A and the diode D10. The above-described switching regulator IC4 is connected to the terminals IG1 and IG2 at the input side, and is connected to the power source terminal Vce of the microcomputer 240 at the output side. The capacitors Cl and C2 are provided at the input of the regulator IC4, and the capacitors C3 and C20 are provided at the output of the regulator IC4. The gates IC5B and IC5-C, the resistors R70 and R71 and the capacitor C24 form an unstable multivibrator the output of which is supplied to the reset terminal RES of the microcomputer 240 through the resistor R56. This multivibrator 1 oscillates or stops oscillating in accordance with the signal level at the other input terminal (forbidden terminal) of NAND gate IC5-B. This control signal is generated by applying a signal generated by the circuit formed by the resistors R54, R65 to R66, the capacitor C22 and the NOR gate IC5-A (which signal is in sync hronism with the period of the pulse appearing at the po,rt B5 of the microcomputer 240) to a time constant circuit formed by resistors R67 to R69, the capacitor C23 and diode D3. When the capacitor C23 is charged to a voltage higher than the input threshold value of the NAND gate IC5-B, oscillation is stopped, whereas when the charged voltage is lower than the input threshold value, oscillation is allowed. During the oscillation period, resetting is repeated by the output. The NAND gate IC5-D receives at one input terminal thereof the signal which is also applied to the input terminal of the NAND gate IC5-B of the multivibrator, and receives the output of a time constant circuit (which is connected to the power source terminal Vec and is formed by capacitor C29 and resistor R84) via a resistor R16 at its other input terminal. The output of the NAND gate IC5-D is inverted by the inverter IC3-D, and controls the transistor IC6-A through the diode D9. In other words the level of the terminal HEAD1 is forced to become I'Ll' (low) level (the level at which headlamp is turned on) when the computer 240 or falls i.n runaway. The diodes D9 and D10, the output port BO of the microcomputer 240 and the inverter IC3-D form the circuit to make control of transistor IC6 A possible.
The operation of the apparatus will now be explained. When the terminals HEAD1 and HEAD2 are selected or closed, the terminals AUTO9 HEAD1 and HEAD2 of the unit 24 become ON and the headlamps 26A and 26B are turned on by the drive of the relays 28A and 28B.
Further, when the terminal AUTO is selected or closed, 1 1 Q 1 all the terminals SMALL, HEAD1, HEAD2 and AUTO of the unit 24 are then OFF and the relays 28A and 28B are au tomatically controlled in accordance with output of the light sensor 25, so that' the headlamps 26A and 26B are turned on or off in accordance with the output of the light sensor.
In this case, except in the automatic mode the terminal AUTO of the unit 24 is ON, surely is ON because of the two systemsy preventing the misunderstanding that high illumination intensity exists which results in the grounding line trouble (such as a line break) and thus preventing erroneous turning off of the headlamps. Also, all of the terminals are open in the automatic mode, making the automatic mode the most stable condition.
The double connections to earth or ground as described above are used on the understanding that the output voltage of the light sensor 25 is proportional to the amount of light sensed. However, if the output voltage of the. sensor 25 is innversely proportional to the amount of light sensed, then the double systems will be connected to the positive power supply line.
The operation of the apparatus to detect abnormal conditions will now be explained.
A. Trouble Detection for Power Source System The-power source is supplied to the terminals IGI and IG2 of the unit 24 and is applied to the switching po er source ic4 through the diodes D1 and D2. The output of the power source 1C4 is supplied to the microcomputer 240 etc. The same voltage is applied to the circuits comprising the diodes D12 and D13, and is therefore applied to the terminals C2 and C3 after being inverted by the inverters IC3-A and IC3-B. While the l- normal battery voltage is applied to the terminals IG1 and IG2, both of the terminals C2 and C3 of the microcomputer 240 become I'Ll' level.
If trouble occurs and the fuse of either the terminal IG1 side or the terminal IG2 side melts, or the connector has a loose contact, different input levels are generated at the terminals C2 and C3, for example if the fuse melts (or the connector is loosened) at the terminal IG1 side while the terminal IG2 side is normal, the terminal C2 becomes I'Ll' and the terminal C3 becomes "H" whereas, in the case where the fuse melts the terminal IG2 side (or the connector is loosened) while the terminal IG1 side is normal, the terminal C2 becomes "H" and the terminal C3 becomes 11L11.
When such a level difference is generated between the terminals C2 and C3, the port B4 of the microcomputer. 240 becomes I'Ll' indicating a power source trouble. As a result, the warning lamp 37 is turned on, and the trouble detection is indicated to the driver.
P, Since the terminal IG2 is normally I'Ll' while the starter motor is being rotated, the warning lamp is only turned on a few periods after the level difference between the terminals C2 and C3 is generated. This delay may be obtained with a hardware impelementation.
B. Trouble Detection for Headlamp Driving System In the lit or ON conditions of the headlamps in accordance with the ambient light conditions both of the ports BO and Bl of the microcomputer 240 become I'LlI, and the outputs of the open-collector transistors IC6-A and IC6-C become 11L11. The relays 28A and 28B connected to the terminals HEAD1 and HEAD2 are thus driven to turn on the headlamps 26A and 26B. At this time, the outputs of i 1 1 the inverters IC3-E and IC3-F, in other words the inputs of the terminals CO and Cl of the microcomputer 240, are both "H".
However, when the headlamps are off, the terminals HEAD1 and HEAD2 become "H?' through the coils of the relays 28A and 28B, and both of the terminals CO and Cl of the microcomputer 240 become TIL11.
I. Headlamp OFF Condition Example (i) In the case where the port BO or Bl of the microcomputer 240 becomes I'Ll' level due to trouble, for example when the signal level at-the port BO becomes I'LlI, the output of the open-collector transistor IC6-A becomes _11L11 (low) and the headlamps are turned on. In this condition, the output of the inverter IC3-E, in other words the level of the terminal CO of the microcomputer 240, is ??H" (high). At t his time, the level of the terminal Cl is 11L11.
The port B4 of the microcomputer 240 is therefore driven to become I'Ll' indicating that trouble is occurring by the level difference between the terminals CO and Cl so that the warning lamp 37 is turned on. A buzzer may be used instead of,or in addition to, the warning lamp 37.
Usually, the driver does not realise thatthe headlamps have been turned on, so this alarm syst.em is useful.
Example (ii) In the case where the input or the output of one of the open-collector transistors IC6-A and IC6-C becomes I'Ll' because of trouble, the alarm is transmitted in the same way as in Example (i) above. - Example (iii)
In the case where trouble occurs at the relay 28A (28B), connected to the terminal HEAD1 (HEAD2), such as a coil break, a connector disconnecting or a loose contact with a connector, the input of the inverter IC3-E (IC3-F) is fixed to be I'Ll' by the resistor R31 (R32), and the terminal CO (Cl) becomes "H". As a result, the microcomputer 240 judges that trouble is occurring, the output at the port B4 becomes I'Ll' and the lamp 37 is turned on.
Since the above described trouble or problem d.etection is done in the daytime when the headlamps are not necessary and the alarm is indicated, the driver can be aware of the problem and can drive safely at night if the defective part causing the problem is immediately repaired.
II. Headlamp-ON Condition Example (i) In the case where the port BO or the port BI of the microcomputer 240 does not-become I'Ll' because of trouble or a problem (i.e. where the headlamps are turned or maintained ON by only one of the terminals HEAD1 and HEAD2.), for example in the case where the port BO does not become I'LlI, only the port BI becomes I'Ll' so that the output of the inverter IC3-F is "H", and the trouble thus is detected. The trouble is detectable if the cause of trouble is, for exampleg disconnection at the soldering joint of the printed circuit board or pattern problem.
Example (ii) In the case where the input or output of one of the opencollector transistors IC6-A and IC6-C is causing trouble, the trouble is detected in the same way as in Example (i).
The operation of. the apparatus in the case where the microcomputer 240 fails is decribed next. First of 9 4 i all, when the microcomputer 240 operates normally, pulses are generated at the port.B5 with a constant period. As the pulse is differentiated by the capacitor 22, the output of the NOR gate IC5-A. becomes "H" (high) synchronizing with the period of pulse of the port B5. The output pulse of the NOR gate IC5-A is applied to the capacitor 23 through the circuit formed by the parallelconnected resistors R67 and R68, and the capacitor 23 is char ged. The width and frequency of the pulse are arranged to be sufficient to charge the capacitor 23.
In the case where the charging voltage ofthe capacitor 23 is higher than the input threshold value of the NAND gate IC5-B which forms part of the unstable multivibrator, the unstable multivibrator does not oscillate. The output of the NAND gate IC5-D becomes I'LlI, and the output of the latter inverter IC3-D becom-.s "H".
Under normal conditions, when the port BO is driven to become I'Ll' (low) by the microcomputer 240, the terminal HEAD1 also becomes I'Ll' and the headlamps are turned on in the. case of the light control apparatus for a vehicle, If the microcomputer 240 fails in runaway or crashes for some reason, the port B5 becomes "H" or I'LlI, and the input of the NOR gate IC5-A becomes "H", so that a I'Ll' signal is output from the gate IC5-A. Therefore, the capacitor C23 is discharged with a time constant RC determined by the value of the capacitor C23 and resistor R68 and when the voltage of the capacitor decreases below the input threshold value of the NAND gates IC5-B and IC5-D, the unstable multivibrator begins oscillating, and the oscillating p ulse is applied to the microcomputer 240 as a reset pulse. When the reset pulse is applied to the microcomputer 240, it normally starts, and the pulse 1 1 appears again at the port B5. Therefore the multivibrator stops oscillating.
However, the output of the NAND gate IC5-D simultaneously becomes "H" when the multivibrator begins oscillating, so that the output of the inverter IC3-D becomes I'LI1. As a result, the transistor IC6-A is driven and the terminal HEAD1 is forced ITLI1. Thus, the terminal HEAD1 is forced to stay I'Ll' when the microcomputer 240 fails in runaway, and load driving (lighting of headlamps) is maintained. This load driving continues while the reset is repeated, in other words whilst the trouble is occurring, and provides a so-called fail-safe function.
When the power source is turned on, the capacitor C23 is in the discharging condition in which the failsafe function is actuated because the output of the NAND gate IC5-D is forced to become I'Ll' during a time equal to the time constant RC determined by the values of the capacitor C29 and resistor R84 just after the power source is switched 0Ny so there is no misoperation when the apparatus is initially switched on.
Figure 3 shows a modification of the circuit 241 for use in the case where only one headlamp relay is provided and in which the output terminals of opencollector transistors Ieb-A and Ieb-C are connected to each other and to the terminal HEAD1 (HEAD2).
With the circuit shown In Figure 3, where an output does not appear at the port BO or Bl, the warning lamp 37 is turned on when the open- collector transistor Ieb-A or Ieb-C fails or disconnection occurs at a soldered portion so that the problem can be transmitted to the driver.
Also, -a loose connection of the headlamp relay or 1 i 1 IF disconnection or a break in the coil can be detected, and the warning lamp 37 is turned on when one of these troubles is detected.
Thus, with the apparatus described above, by providing two systems for the power source, when a system or accessory problem and fuse melting due to misconnection occurs, the automatic function is not damaged and erroneous switching OFF of the headlamps can be prevented. Further, in the case of the power source being disconnected due to a loose connection, high reliability can be maintained by providing two systems.
Regarding the connection of the light sensor to control unit, by providing two systems for the ground lines and the power source- (+) lines, misunderstanding that high illumination intensity exists can be avoided and safety is maintained. By providing a switching unit in which the switches are all open for the automatic mode, the automatic mode is obtained as the most stable condition. Alt;o with the headlamp driving relays in parallel, the reliability of the driving system is enhanced and the reliability of whole apparatus is therefore improved.
By providing two power source and driving systems with the trouble detection circuits, trouble in one system can be immediately detected and indicated, the driving period of the one system can be shortened as soon as possible and high reliability' can be maintained. As described above, by using the pulse appearing at the port B5 when the microcomputer 240 operates normally the capacitor C23 is charged, causing the unstable multivibrator to oscillate, the microcomputer is reset when the charging voltage becomes lower than a constant voltage due to microcomputer runaway. However, since NAND gate IC5-D connection forces the level of the output terminal HEAD1 to a predetermined level when during a load, if the microcomputer falls in runaway during the period for recovery by repeating reset, load driving remains possible and a fail-safe function is thus provided. Therefore, in case of the headlamp control apparatus, the problem of abrupt turning off of the headlamps at night can be prevented and safe driving can be facilitated. Further by providing a time constant circuit so as to stop the fail-safe function at the time when the power source is actuated, misoperation at the time of switching on of the power source is prevented and smooth driving can be expected.
Thus, the apparatus described adopts two systems for the power source supply and the headlamp.driving in the light control apparatus. In addition, the apparatus employs a structure and connections which enable the stability and reliability of the apparatus to be improved. Thus by detecting a necessary terminal signal level of the control unit and by inputting the signal to the' microcomputer enclosed in the control unit, a judgement whether trouble exists or not can be made by determining a level difference as described above. A warning device in the form of a lamp and/or a buzzer is provided to indicate the existence of such trouble. Further all the terminals of the switching unit are open when the automatic mode is selected. Also, a fail-safe arrangement is provided to maintain headlamp operation if the computer itself fails and loses controlling function.
Reference is hereby directed to co-pending Patent Application No. 2170634 from which the present Application has been divided.
Sk Z 4 1
Claims (4)
1. Apparatus for enabling the headlamps of a vehicle to be controlled automatically in response to ambient light levels ou tside the vehicle, in which apparatus control means are provided to control the headlamps of a vehicle in response to ambient light levels and means are provided for maintaining operation of the headlamps should the control means fail, the maintaining means comprising a capacitor connected to receive a pulsed signal from the control means to charge the capacitor, an unstable oscillatory circuit arranged to commence -oscillation when the capacitor is charged to a predetermined voltage to apply a reset signal to the control meansy and a by-pass circuit for supplying signals to maintain the headlamps in an on condition when the capacitor discharges so that operation of the headlamps is maintained even if the control means fails.
2. Apparatus according to claim 11 wherein the unstable oscillatory circuit comprises an unstable multivibrator.
3. Apparatus according to claim 1 or 2 wherein the control means comprises a microcomputer.
4. Apparatus for controlling the headlamps of a vehicle substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 and 2, or Figures 1 and- 2 as modified. by Figure 3, of the accompanying drawings.
Published 1988 at The Patent Office, State House, 6571 High Holborn, London WC11R 4TP. Further copies May be obtained from The Patent OMce. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd. St Mary Cray, Kent. Con. 1187.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59275132A JPS61150847A (en) | 1984-12-25 | 1984-12-25 | Control device for car lighting equipment |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8805046D0 GB8805046D0 (en) | 1988-03-30 |
| GB2201053A true GB2201053A (en) | 1988-08-17 |
| GB2201053B GB2201053B (en) | 1989-04-19 |
Family
ID=17551140
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8531246A Expired GB2170634B (en) | 1984-12-25 | 1985-12-19 | Light control apparatus for a vehicle |
| GB8805046A Expired GB2201053B (en) | 1984-12-25 | 1988-03-03 | Light control apparatus for a vehicle |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8531246A Expired GB2170634B (en) | 1984-12-25 | 1985-12-19 | Light control apparatus for a vehicle |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4728861A (en) |
| JP (1) | JPS61150847A (en) |
| DE (1) | DE3545924A1 (en) |
| FR (1) | FR2575119B1 (en) |
| GB (2) | GB2170634B (en) |
Families Citing this family (28)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4891559A (en) * | 1985-06-13 | 1990-01-02 | Nippondenso Soken, Inc. | Apparatus for controlling a headlight of a vehicle |
| JPH0815858B2 (en) * | 1986-11-22 | 1996-02-21 | 日産自動車株式会社 | Lighting device for steering wheel switch |
| JPH07108639B2 (en) * | 1987-01-22 | 1995-11-22 | 日産自動車株式会社 | Vehicle headlamp lighting control device |
| JPS63255141A (en) * | 1987-04-13 | 1988-10-21 | Nissan Motor Co Ltd | Head lamp device for vehicle |
| US4862036A (en) * | 1987-12-07 | 1989-08-29 | Kriss Ii George H | Electrical circuit for controlling the operation of high intensity motorcycle lamps |
| US5081625A (en) * | 1988-10-05 | 1992-01-14 | Ford Motor Company | Watchdog circuit for use with a microprocessor |
| JPH02179551A (en) * | 1988-12-29 | 1990-07-12 | Nissan Motor Co Ltd | Lamp disconnection alarming device for vehicle |
| US5124549A (en) * | 1990-10-15 | 1992-06-23 | Lectron Products, Inc. | Automatic headlamp dimmer with optical baffle |
| IT1245577B (en) * | 1991-03-22 | 1994-09-29 | Giuseppe Codrino | SOLID STATE DEVICE, FOR CHECKING THE LAMPS OF A VEHICLE AND INGLOBAL OF THE PILOTING, PROTECTION AND DIAGNOSTIC CIRCUITS, SUITABLE TO GUARANTEE CORRECT OPERATION |
| FR2689072A1 (en) * | 1992-03-31 | 1993-10-01 | Valeo Vision | Lighting and / or signaling device used in a foggy situation. |
| DE4341058C1 (en) * | 1993-12-02 | 1995-04-27 | Daimler Benz Ag | Light control device for a motor vehicle |
| US5438237A (en) * | 1993-12-06 | 1995-08-01 | Autosmart Light Switches, Inc. | Automatic daytime running light system |
| US5614788A (en) * | 1995-01-31 | 1997-03-25 | Autosmart Light Switches, Inc. | Automated ambient condition responsive daytime running light system |
| DE19610871C1 (en) * | 1996-03-20 | 1997-06-19 | Daimler Benz Ag | Vehicle brake light control device |
| JP3729961B2 (en) * | 1997-01-14 | 2005-12-21 | 株式会社小糸製作所 | Discharge lamp lighting circuit |
| JPH10278668A (en) * | 1997-04-08 | 1998-10-20 | Nissan Motor Co Ltd | Illumination control device for vehicle |
| DE19738851A1 (en) * | 1997-09-05 | 1999-03-11 | Bosch Gmbh Robert | Control device for operating and controlling gas discharge lamps in headlights |
| DE69918185T2 (en) | 1998-10-12 | 2005-06-30 | Control Devices, Inc. | NATURAL LIGHT SENSOR. |
| DE19911901C5 (en) * | 1999-03-17 | 2010-01-28 | Daimler Ag | Vehicle lighting device with driving situation-dependent lighting control |
| JP2001138799A (en) * | 1999-08-30 | 2001-05-22 | Koito Mfg Co Ltd | Lighting system for vehicle |
| DE20011115U1 (en) * | 2000-06-23 | 2000-09-07 | Reitter & Schefenacker Gmbh | Monitoring device of a control, preferably for signal lights of vehicles, in particular motor vehicles |
| JP2002025790A (en) * | 2000-07-12 | 2002-01-25 | Koito Mfg Co Ltd | Discharge lamp lighting circuit |
| US20040217258A1 (en) * | 2003-04-30 | 2004-11-04 | Clugston P. Edward | Solar sensor including reflective element to transform the angular response |
| JP4468983B2 (en) | 2007-12-12 | 2010-05-26 | 矢崎総業株式会社 | Load control device |
| US8982578B2 (en) * | 2010-10-14 | 2015-03-17 | Tyco Electronics Corporation | Connector system and assembly having integrated protection circuitry |
| CN105365671A (en) * | 2015-12-08 | 2016-03-02 | 徐州一呼机械制造有限公司 | Brake lamp fault prompting circuit |
| CN107160131A (en) * | 2017-06-21 | 2017-09-15 | 南京理工大学 | Electronics fool proof material barrel |
| CN113459941A (en) * | 2021-07-20 | 2021-10-01 | 南京科技职业学院 | Car intelligent headlamp self-adaptive system based on single chip microcomputer |
Family Cites Families (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB839180A (en) * | 1957-10-17 | 1960-06-29 | Honeywell Regulator Co | Improvements in or relating to control systems, especially aircraft control systems |
| GB953473A (en) * | 1960-12-22 | 1964-03-25 | Vickers Armstrongs Aircraft | Improvements in control systems |
| NL274016A (en) * | 1961-01-26 | |||
| US3289193A (en) * | 1963-10-22 | 1966-11-29 | Bendix Corp | Monitoring system for redundant systems |
| GB1219262A (en) * | 1966-10-20 | 1971-01-13 | Charles Richard Edwards | Safety apparatus for controlling circuits |
| GB1272834A (en) * | 1968-06-24 | 1972-05-03 | Westinghouse Electric Corp | Control system |
| GB1318405A (en) * | 1969-09-11 | 1973-05-31 | Ver Flugtechnische Werke | Switching system for a three-chennel flight control system |
| US3919885A (en) * | 1972-03-24 | 1975-11-18 | Harbeke Gerold J | Apparatus for dynamically analyzing an electronic fuel injection system and the associated engine parts |
| US4058793A (en) * | 1976-05-24 | 1977-11-15 | Copeland William G | Vehicle headlight warning circuit |
| ES462310A1 (en) * | 1976-10-28 | 1978-12-16 | Renault | Control device for automobile electric equipments |
| US4139801A (en) * | 1977-01-26 | 1979-02-13 | Linares Raul F | Automatic automobile light control system |
| US4376909A (en) * | 1979-04-13 | 1983-03-15 | Honda Giken Kogyo Kabushiki Kaisha | Automatic light control for automotive vehicles |
| FR2458817A1 (en) * | 1979-06-06 | 1981-01-02 | Commissariat Energie Atomique | METHOD FOR MONITORING THE INSTANTANEOUS STATE OF AN ELECTRIC CIRCUIT AND IN PARTICULAR FOR DETECTING A BREAK OF THIS CIRCUIT |
| GB2060967A (en) * | 1979-09-17 | 1981-05-07 | Radiovisor Patent Ltd | Intruder alarm system |
| JPS5747231A (en) * | 1980-09-05 | 1982-03-18 | Nippon Denso Co Ltd | Warning method and apparatus used for vehicle |
| GB2088107B (en) * | 1980-11-06 | 1984-08-01 | Shorrock Security Systems Ltd | Arrangement for detecting the breaking of window glass |
| US4477870A (en) * | 1982-05-26 | 1984-10-16 | Westinghouse Electric Corp. | Digital control system monitor having a predetermined output under fault conditions |
| JPS5948243A (en) * | 1982-09-13 | 1984-03-19 | Nissan Motor Co Ltd | Light controller for vehicle |
| US4446507A (en) * | 1983-03-29 | 1984-05-01 | Daniels Ronald M | Automobile headlight control system |
| US4613791A (en) * | 1984-02-02 | 1986-09-23 | Honda Motor Co., Ltd. | Automatic light control apparatus for vehicle |
-
1984
- 1984-12-25 JP JP59275132A patent/JPS61150847A/en active Granted
-
1985
- 1985-11-27 US US06/802,764 patent/US4728861A/en not_active Expired - Fee Related
- 1985-12-19 GB GB8531246A patent/GB2170634B/en not_active Expired
- 1985-12-23 DE DE19853545924 patent/DE3545924A1/en not_active Ceased
- 1985-12-24 FR FR8519155A patent/FR2575119B1/en not_active Expired - Fee Related
-
1988
- 1988-03-03 GB GB8805046A patent/GB2201053B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3545924A1 (en) | 1986-07-10 |
| GB2170634B (en) | 1989-05-04 |
| FR2575119A1 (en) | 1986-06-27 |
| GB8805046D0 (en) | 1988-03-30 |
| GB8531246D0 (en) | 1986-01-29 |
| JPS61150847A (en) | 1986-07-09 |
| US4728861A (en) | 1988-03-01 |
| JPH0230893B2 (en) | 1990-07-10 |
| FR2575119B1 (en) | 1991-05-17 |
| GB2201053B (en) | 1989-04-19 |
| GB2170634A (en) | 1986-08-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| GB2201053A (en) | Failsafe headlamp control apparatus for a vehicle | |
| US5030938A (en) | Universal trailer lighting adapter | |
| US5349994A (en) | Control system for filling tanks with liquids | |
| US4689573A (en) | On-vehicle diagnostic unit for electronic ignition systems | |
| KR100247115B1 (en) | Car battery discharge preventing apparatus | |
| JPS63202217A (en) | Circuit supplying power to a plurality of loads | |
| EP0626743B1 (en) | Line fault monitoring apparatus | |
| US4743888A (en) | Device for detecting a trailer coupled onto a tractor vehicle | |
| US6049139A (en) | Method and apparatus for detecting abnormality of cable having electrical conduction line surrounding power supply line used in car | |
| US4568923A (en) | Fire alarm system | |
| US4607246A (en) | Malfunction indicating method for vehicle-mounted DC generator | |
| JPS642772B2 (en) | ||
| KR200214212Y1 (en) | Battery discharge protection and tail and fog light controls | |
| US4871945A (en) | Automatic brake light flashing electric module and circuit | |
| KR100552771B1 (en) | automatic light system of vehicle | |
| US20130176119A1 (en) | Vehicle alarm with protection against power source and wiring tampering | |
| JP3052652B2 (en) | Vehicle lamp drive | |
| JPH0251776B2 (en) | ||
| CN211653498U (en) | Control circuit of double-circuit DC-DC start-stop voltage stabilizer for vehicle | |
| SE435479B (en) | ELECTRICAL COUPLING DEVICE FOR FLASH LIGHTS FOR MANUALING LIGHT SIGNALS AND FOR REPLACING LIGHT LIGHT LIGHT LIGHTS | |
| JPH0151875B2 (en) | ||
| JPS63818B2 (en) | ||
| JPH0157452B2 (en) | ||
| JPH0230160Y2 (en) | ||
| KR0115757Y1 (en) | Fault detecting device of a.b.s. alarm light |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20001219 |